Using search engine logarithmic scales

I have a problem for work that is stirring up lots of memories of University Math courses, and I need help!

I work in search engine optimization, and search engines use logarithmic scales to value pages and websites. I'm using a tool that mimics those scales and assigns a number between 1 and 100 to the value and importance of a page on the internet. I understand that the difference between a page with 'pagerank' 4 has 10x the value of a pr 3. But this particular tool breaks it into fractions, so I'm trying to compare for example a page with PR 34 and a page with PR 41. How can I create a fixed number that better represents the relative importance?

Also, there are two logarithmic 'scores' given, one for the page (PR) and one for the domain (DR). Does anyone have any suggestions for how to combine the two into a single number that could be compared against a second 'set'. For example, page A has a PR 34 and DR 55, compared with page B with a PR 30 and DR 58. I'm going to assume both scores are weighted equally.